反应详情

A solution of 1,5-dibromopentane (5 gms, 23.15 mmol) in dry THF (10 ml) was added slowly to a suspension of Magnesium turning (2.8 gms, 112 mmole) in dry THF (50 ml) and catalytic amount of iodine under nitrogen atmosphere. After the addition of about 3 ml of dibromopentane solution in THF, Grignard reaction was initiated. The addition was continued maintaining a gentle reflux. The mixture was refluxed for 16 hours to complete the formation of the Grignard reagent. To the reaction mixture was added a solution of a solution of δ-valerolactone (2.13 gms, 21.3 mmol) in dry THF (50 ml). The resulting mixture was refluxed for 6 hours under nitrogen and then quenched by addition of saturated solution of ammonium chloride at 0° C. The product was extracted in ethylacetate. Organic layer was washed with water, brine and dried over anh. Na2SO4. Drying agent was filtered off and the solvent was removed under vacuum to give 2.7 gms of diol (8), which was used without any further purification in the next step.

1. additionThe addition
2. temperaturewas continued maintaining a gentle reflux
3. temperatureThe mixture was refluxed for 16 hours
4. temperatureThe resulting mixture was refluxed for 6 hours under nitrogen
5. customquenched by addition of saturated solution of ammonium chloride at 0° C
6. extractionThe product was extracted in ethylacetate
7. washOrganic layer was washed with water, brine
8. dry with materialdried over anh. Na2SO4
9. customDrying agent
10. filtrationwas filtered off
11. customthe solvent was removed under vacuum